Electrical connections between terminal pins and flat conductors on a flat flexible dielectric substrate are known in the art. Typically, a terminal pin either is utilized to punch through the flat conductor and the flexible substrate to establish an electrical and mechanical connection between the pin and the conductor, or slits are formed in the flat conductor and substrate to facilitate penetration of the pin. The slits form "flaps" which engage sides of the pin.
In order to assure good electrical and mechanical connections in these types of electronic devices, solder or other adhesives often are used. For instance, in U.S. Pat. No. 4,970,624, dated Nov. 13, 1990 and assigned to the assignee of the present invention, uni-axial adhesive is deposited on the flat conductor about the aperture which is penetrated by the terminal pin. The adhesive includes a non-conductive base incorporating randomly spaced conductive particles. When the terminal pin is forced through the adhesive, a portion of the adhesive is carried with the terminal pin between the pin and the flat conductor. The carried portion of the adhesive is compressed for establishing contact between the conductive particles and, thereby, conductivity between the terminal pin and the flat conductor, leaving the adhesive other than that portion in a non-conductive state. Such adhesives often are called "Z-axis" adhesives.
Although such electrical connections generally serve their intended purposes, the use of solder materials, conductive adhesives, Z-axis epoxy and other similar materials require secondary operations to establish conductivity between the terminal pin and the flat conductor on the flat flexible substrate. In addition to the time and expense of the secondary operations, the materials, themselves, are relatively expensive. The present invention is designed for solving these problems and eliminating the need for solder or other conductive materials by establishing an electrical connection directly between the terminal pin and the flat conductor on the flat flexible substrate, by having a similar metal interface between the pin and the flat conductor and by controlling various parameters of the pin and the substrate.